Propeller



May 10, 1938. El w AUSTLN 2,116,818

. PROPELLER Filed June 6. 1956 3 Sheets-Sheet 1 v INVENTOR. /3 www May 10, 1938. E. w. AUSTIN 2,116,818

v PROPELLER Filed June 6, 1956 I5 Sheets-Sheet 2 E. W. AUSTIN may m, 1938.

PROPELLER Filed June e, 1956 3 smeg-sheet 3 INVENTOR,

Patnled May l0, 1938 UNITED STATES .PATENT OFFICE PROPELLER 4 Ellsworth W. Austin, Cedar Rapids, Iowa Application June 6, 1936, Serial No. 83,912

14 Claims.

This invention relates to automatic variable pitch propellers and more particularly to the type wherein the blades may be retained at any selected position of adjustment.

Heretofore, automatic variable pitch propeller-s have been found to be lacking in advantages which are present in propellers that may be controlled by the operator. There is a distinct advantage in many instances. in having the blades lo remaining fixed in their adjustment rather than to have them constantly changing as in the case with most types of automatic propellers. In operating a device constructed in accordance with my latest invention, the engine may be accelerll ated to any desired speed and by a simple control means the blades retained in the adjusted position acquired when operating as an automatic adjustable propeller. Likewise if a low pitch adjustment of the propeller blades is de- 20 sired even though the engine may be accelerated to a relatively high speed, such as might be the case in taking oi, this low pitch may be retained by the simple hydraulic valve control.

Hence, one of the objects of my invention is to 25 provide an automatic propeller constructed for the purpose of applying control means to retain any selected position of adjustment.

Another object of the invention is to provide a simple positive lever device to turn the pro- 30 pellerblades by centrifugal force.

Another object is to provide a suitable resisting spring to balance the net force tending to advance the pitch. n Another object of the invention is to provide an hydraulic cylinder with piston arranged to secure any desired adjustment of the blades when an operating valve is closed.

. An object is also to provide an automatic va- L riable pitch propeller that is safe, durable, light in weight, and easilyrnanufactured at a relatively iov! cost.

These and further objects will 'oe more fully .videnced from a study of the following descripim. and accompanying drawings, wherein like 1acters represent like parts throughout the l ral Views:

Fig. l is a rear View7 of a propeller embodying one form of the present invention, the blades .ing partially broken away.

Fig. 2 is a side elevation partiaily in section,

(ci. 17o- 163) Fig. 4 is a top view of one of the three point levers.

Fig. 5 is an end view of the annular member shown in Fig. 2.

Fig. 6 is a fragmental view showing a portion of the annular member and lock ring.

Fig. 7 is a top plan view of one of the blades.

Referring to the drawings, and more particularly to Fig. 1 and Fig. 2, wherein a three bladed propeller is shown in general to comprise a hub I0 with stub portions II upon which are mounted shell blades I2. Conventional thrust and radial bearings I4 and I5 are respectively secured to the stubs Il by threaded Spanner nuts I6, and lock nuls I1 and I8. Locks I9 are positioned between nuts I1 and IB in the usual method, engagement of the locks being made with l-:eyways cut in the stubs. One of these keyways is shown in 2. An intermediate collar. 2l is provided to retain the rollers of thrust bearing I4. Also a shoulder collar 22 is provided outside the radial bearing I5 for the purpose of definitely locating the end of propeller blade I2 during'the assembly of the same within the blade sleeve I3. 'I'he latter being scallopped along its outer edge for depositing an electrically welded bead at 23 to unite the blade I2 with sleeve I3 as a solid assembly. A sealing Washer 24 is provided at the base of each blade and further, packing 25 is added to retain the grease in and around the bearings. A seal 26 is incorporated within radial bearing l5 and conventional pressure grease f1ttings 2l are provided in the usual manner being tapped into the cylindrical surface of the blade sleeves I3.

Referring to hub l0 it will be understood that the usual splines |09 are provided for mating with corresponding splines on an engine shaft, a portion of which is shown in Fig. 2 as II and con- Ventional conc Ill2 is used to space the propeller on the engine shaft while the usual split cone |03 and Spanner nut |64 provide means for drawing the hub snugly into place on the engine shaft IUI.

Further referring to hub I0 it will be noted that an axially extended portion provides a smooth cylindrical bore at |05 into which is fitted piston IUE. with cup packings I0' and 1I provided back to back in a manner conventional for two. way hydraulically operated cylinders. IDB is a thin spring washer having its outer lip in the form of extending lingers pressing outward to insure a scaling of the inner cup packing 1I. As a support for the cup packings IIJI` and 1I and spring washer Hi8, a flanged piston core |09 is provided and threaded externally to receive the inner collar which is welded as a part of the annular member assembly generally designated as H0. A taper threaded locking bushing 2B is screwed within the piston 'core |09 to bind the inner collar in a manner often. employed. Further referring to annular member H0, itwill be noted that this is arranged concentrically with the propeller hub and has the spider 3 securely welded to the sleeve H2. A slightly turned up flange on the outer end of the latter being provided for location at assembly. Sockets ||4 are equally spaced about the outer flange of the spider ||3 and have locating stems 3| piercing the outer flange of the spider.

In order to guide the annular member and retain it concentrically with the hub l0, an internally threaded cap 32 is provided which has a bushing 33 pressed in place as a wearing member. Cap 32 also provides a means to retain the spring 34 which is of a type suitable to act under combined torque and compression loads and is arranged within the cylindrical portion of hub I0 in such a manner that a compressive bearing of the spring 34 is had between the piston |06 and cap 32 and torsional resistance of the spring is obtainedwhen the end of the inner most coil is retained in a recess at 35 of the piston |06I and the end of the outer most co'il is retained within the hub at 36 in cap 32.

The propeller blade sleeves are provided with universal connectors or ball sockets 40 which receive the balls 4| of the three point lever 42. In the case of a three bladed propeller as shown in Fig. 1 a three point lever is lplaced between adjacent blades and connected thereto to cause slight change in blade pitch, when a thirdball 43- of the lever 42, is moved by action of the receiving socket ||4. Plates 44 are arranged to retain the balls 43.` Bolts and nuts at 45 secure the plates 44 in place.

' An examination of the three point levers 42 and the method of mounting them will point out that in service their Weight will tend to cause these levers to be displaced radially bycentrifugal action, in respect to the axis of the propeller. Because of the universal connections at ||4 a rotation is had of annular member D and likewise an axial movement, for in changing positions such for instance as from A" to B shown in Fig. land Fig. 2, the ball ends 43 of levers 42 are considerably extended in a direction axial to the hub and away from the blade centerline.

Acting as counterweights aiiectedby centrifugal force, levers 42 are constructed with relatively massive central portions and light end portions. The central portions of the levers play an important part as weight members, however in general they are contributaryas links or levers connecting adjacent blades for simultaneous adjustment.

In the position A shown in Fig. 1 and Fig. 2, the central portions of the levers 42 are moved inward to a considerable degree and-the rotative movement of the annular member I0 in a clockwise direction viewed from the outer end as in Fig. 5, is responsible for a sort of -Wrapping of the levers about the hub I0. In the position of full retraction the massive central portions of levers 42 are practically brought to bear against the hub.

Subsequently to the foregoing, it may be as sumed that the device is being operated at a speed sufficient to exert a centrifugal force on the massive central portions of the levers, thus causing an unwrapping or outward motion of these in respect to the propeller hub and consequently annular member |||I` is moved. Thenew positions of levers after the outward movement mentioned, maybe such as shown by solid lines on the drawings and indicated as B. Ball ends 43 provide universal connections for the levers that the aforementioned unwrapping may not be restricted within the working range.

Ball ends 4|- likewise connect adjacent blade -members, one being universally connected in a socket on the leading side of one blade and the other in a socket on the trailing side of an adjacent blade. Thus as wrapping or unwrapping of the levers occurs, a responsive tilting of the levers results in movement of the blades.

Thus it may be assured that movements of the ball ends 4|, 4| take place about the center C of each lever as shown in Fig. 4 and in equal amounts. Further it may be assumed that movement of the previously mentioned ball ends 43 may also be about the center C of each of their respective levers. The latter movements, however, are not geometrically restricted to the planes of the former, each moving in its individual spiral or helix about the hub. In brief, an outward movement of the central portion of a lever results in rotation or tilting about the central point C which is equidistant to ball ends 4|, 4| these being arranged to freely self center, in their respective universal connectors.

It should be note-d that in service the angularity of the blades may alter in adjustment, nine deg'rees or more and thus to accommodate the slight variation in center distances between sockets 40, 40 of adjacent blade members, it is necessary to have the sockets bored cylindrical as shown, where the balls 4|, 4| enter, such being common ypractice and often employed to allow a slight slippage of the balls in the sockets to compensate for center distance variation. It should be carefully noted from the drawings, especially referring to Fig. 1 that universal connectors 40 are a snug t for the balls 4| in the directions in which forces are applied. l

It should be noted that cap 32 provides'a means for adjustment to vary the spring reaction on the annular member. A locking sleeve 5| is arranged with suitable splines to engage grooves cut in the hub at 38. Fig. 6 best s hows an arrangement for a projection of the locking sleeve 5| to engage suitable slots 50 in cap 32. A desired adjustment for spring pressure may be made by rotating the cap 32 and locking it in position as will be readily understood. To further insure the setting thus made, the headless set screw 3-'| is provided in sleeve 5|.

Many aircraft engines are provided with hollow propeller shafts and in this preferred embodiment such an arrangement is made use of to conduct uid such as oil from a reservoir not shown, within the engine or aircraft. Likewise, a conventional shut-off valve not shown may be installed in the fluid line to the propeller. In service the valve normally remains open and in most cases little or no fluid pressure is applied to move piston |06, however, as the speed of rotation of the propeller increases the three point links 42 will be urged outward by centrifugal force and thus annular member H0 will be slightly rotated and also forced outward in axial direction which results in compressing spring 34 to a degree where equilibrium is again established. Now with the three point links 42 in a position representing a relatively high speed of propeller -to adjust the pitch thereof rotation and thus a corresponding advance in pitch adjustment of the blades I2 having been obtained, it will be easily understood that, by closing the fluid valve mentioned, further motion of piston |06 will be arrested and thus the blade adjustment retained. Obviously by varying the speed of rotation with the valve open, the device operates as a full automatic. On the other hand when the valve is closed any desired setting may be retained. It will be noted that pressure from the spring to further retard the blade setting is prevented by the non-compressible characteristic of the fluid in the cylinder, when the valve in the line is closed. Likewise a net force resulting from centrifugal action sufilciently great to normally increase the blade setting, is arrested under the same conditions, for the reversible or two way arrangement of cup leathers |01 prevents air passing and thus atmospheric pressure is of sulcient value to prevent movement of piston |06.

In some instances, it is desirable to apply iluid pressure to the piston and obtain characteristics of operation suitable to' the needs of conditions then encountered. It will be seen that the utility of my propeller is considerably enhanced by being applicable to various methods of control.

Referring to Fig. 3 wherein a two bladed propeller arrangement is provided, a universal connector socketil is secured to the hub 6I at each side to receive the ball connections of the three point links 42 and obviously the functioning of the device to alter the blade pitch and to be operated by use of the piston |06, is for all practical purposesthe same as described in connection with the three bladed arrangement.

Certain specific embodiments of my invention have been described in detail yet it is to be understood that the particular structures shown are merely for the purpose of disclosing the development in the art and variations of the device may be resorted to within the scope of the invention and members shown may be omitted or others added yet holding to the spirit'of the description and claims.

I claim as my invention:

1. An aircraft propeller comprising a hub, blades adjustably mounted on said hub for pitch variation, `a member mounted on said hub for both axial and rotary movement relative thereto, a three point lever universally connected at two of its points respectively to adjacent blades upon tilting of said lever, said third point of said lever being universally connected to said member, means for positioning said member at various adjusted positions thereof to thereby maintain said third point of said lever in different tain different blade adjustments. i

2. An aircraft propeller comprising a hub, blades adjustably mounted on said hub for pitch variation, a member mounted on said hub for both axial and rotary movement relative thereto, a three point lever universally connected at two of its points respectively to adjacent blades to adjust the pitch thereof upon tilting of said lever, said third point of said lever being universally connected to said member, hydraulic means for resisting action of said member to give various adjusted positions of the same for various blade adjustments.

3. An aircraft propeller comprisingA a hub, blades adjustably mounted on said hub for pitch variation, a member mounted on said hub for both axial and rotary movement relative thereto,

positions to mainmeans for moving the member comprising an hydraulically operated piston, a three point lever universally connected at two of its points respectively to adjacent blades to adjust the pitch thereof upon tilting of said lever, said third point of said lever being universally connected to said member to restrict the movement of the lever for different adjustments of the blade.

4. An aircraft propeller comprising a hub, blades adjustably mounted on said hub for pitch variation, a member mounted on said hub for both axial and rotary movement relative thereto, means for moving the member comprising an hydraulically operated piston, a three point lever universally connected at two of its points respectively to adjacent blades to adjust the pitch thereof upon tilting of said lever, said third point of said lever being universally connected toI said member and to move in a helix or spiral path about the hub.

5. An aircraft propeller comprising a hub, blades adjustably mounted on said hub for pitch variation, a member mounted `on said hub for both axial and rotary movement relative thereto, a three point lever universally connected at two of its points respectively to adjacent blades to adjust the pitch thereof upon tilting of said lever,

said third point of said lever being universally connected to said member, the lever being so constructed and arranged that centrifugal force upon rotation of the hub may act on. the lever to move the said third point of the lever in a helix or spiral about the hub.

6. An aircraft propeller comprising a hub, blades adjustably mounted on said hub for pitch variation, a member mounted on said hub for both axial and rotary movement relative thereto,

a three point lever universally connected at two of its points respectively to adjacent blades to adjust the pitch thereof upon tilting of said lever, said third point of said lever being `universally connected to said member, the lever being so constructed and arranged that centrifugal force upon rotation of the hub may act on the leversto move the said third point of the lever.

'7. An aircraft propeller comprising a hub, blades adjustably mounted on said hub for pitch variation, a member mounted on said hub for both axial and rotary movement relative thereto, a spring arranged to move the member in one direction and a three point lever universally connected at one of its points to move the member in the other direction, said lever connected at two of its'said points respectively to adjacent blades to adjust the pitch thereof upon tilting of the lever. i

8. An aircraft propeller comprising a hub, blades adjustably mounted on said hub for pitch variation, a member mounted on said hub for both axial and rotary movement relative thereto, a springarranged to move the member in one direction and a three point lever universally connected at one of its points to move the member in the other direction, said lever connected at ytwo of its said points respectively to adjacent the hub to adjust the pitch of the blade upon tilting of said lever, said third point of said lever being universally connected to said member, means for positioning said member at various adjusted positions thereof to thereby maintain said third point of said. lever in diierent positions to maintain different blade adjustments.

10. An aircraft propeller comprising a hub, blades adjustably mounted on said hub for pitch variation, a member mounted 'on said hub for both axial and rotary movement relative thereto,

a three point lever universally connected at two of its points respectively to a blade and to the hub to adjust the pitch of the blade upon tilting of said lever, said third point of said lever being universally connected to said member, the lever being so constructed and arranged that centrifugal force may act on the lever to move the member.

1l. An aircraft propeller comprising a hub, blades adjustably mounted on said hub for pitch variation, a member mounted on said hub for both axial and rotary movement relative thereto, a three point lever universally connected at two of its points respectively to a blade and to the hub to adjust the pitch of the blade upon tilting of said lever, said third point of said lever being universally connected to said member, the lever being so constructed and arranged that centrifugal force may act on the lever to move the member, a spring means one end of which is arranged to bear on the member and the other end to bear on the hub to resist the movement of the member both axially and rotatively.

12. An aircraft propeller comprising a hub, blades adjustably mounted on said hub for pitch variation, a member mounted on said hub for to, a three point lever and universal connections for each of the said three points .of the lever to operatively connect the lever to a blade and to the hub and to said member, the lever being so constructed and `arranged that when centrifugal force is effective on the lever an axial and rotary movement is imparted to the member, a tilting f of the lever Vresults and the pitch of the blade is varied.

14. A propeller comprising a hub, blades adjust'ably mounted on said hub for pitch variation, a member mounted on the hub comprising connection points to move in the path of a helix, centrifugally responsivethree point levers normally more or less Wrapped about the hub and universally connected at two of said points respectively to adjacent blades to adjust the pitch Ythereof upon tilting of said lever, said third point of said levers being universally connected to said member at said connection points to take the path of the helix to actuate the member and for centrifugal unwrapping of the lever from the hub.

ELISWORTH W. AUSTIN. 

